AN exploding aerosol can is believed to be the cause of a small fire that started in Rosalind Park this morning.
CFA were called to the scene after a small patch of grass was burnt at 10.20am.
Senior station officer Craig Houlahan said the fire was sparked by a home-made detonating device.
"There's a few of these devices we’ve actually located at fires," he said.
"They're highly explosive and can easily go off."
Firefighters contained the small flames and declared the area of the park behind the old police barracks safe at 10.30am.
Police were also called to investigate.
It comes a day after the special operations bomb squad were called to Huntly to detonate a home-made explosive device.
Station officer Houlahan called for public assistance to help the CFA and police catch offenders.
"We need the public to be vigilant of any suspicious activities," he said.